The faithful segregation of genetic material during cell division is necessary for the development and survival of an organism;errors in this process in humans can result in birth defects and cancer. Essential to the process of cell division is the spindle;a structure comprised of microtubules that associates with chromosomes, enabling the directed movement of genetic material. The spindle can form by two pathways: 1) centrosome dependent, and 2) acentrosomal. Microtubule dynamics are well characterized for the centrosome dependent pathway, but not the acentrosomal pathway;microtubule dynamics in the acentrosomal pathway will be investigated. Motor proteins in the kinesin and dynein family contribute to spindle formation and function. While the contribution of motors such as Eg5, dynein, and Kin I kinesins (MCAK and Kif2a) to microtubule polymerization and transport have been well studied, little is known about the the role of chromokinesins in this process. State of the art microscopy techniques, combined with a powerful in vitro spindle assembly system, will allow studies of spindle dynamics in cells where chromokinesins are perturbed. Quantitative models of spindle formation and organization can then be built.